WO2020025410A1

WO2020025410A1 - Make contact system

Info

Publication number: WO2020025410A1
Application number: PCT/EP2019/069872
Authority: WO
Inventors: Christian Schacherer; Martin Koletzko
Original assignee: Siemens Aktiengesellschaft
Priority date: 2018-08-02
Filing date: 2019-07-24
Publication date: 2020-02-06
Also published as: EP3811391C0; CN112534534A; US11462375B2; EP3811391B1; EP3811391A1; US20210304988A1; CN112534534B; DE102018212953A1; KR20210030467A; JP2021533539A

Abstract

The invention relates to a make contact system for high-voltage applications, characterized in that a vacuum switching tube (28) having two switch contacts in the form of plate contacts (2, 4) is provided, of which at least one is a moving contact (30) coupled to a drive (5), and whereby at least one plate contact (2, 4) is rotationally symmetrically surrounded by a shielding element (32), and the shielding element (32) has an electric conductivity which is less than 40 10^-6 S/m.

Description

description

Locking contact system

Many high-voltage applications require fast grounding of live parts, for example when a network fault occurs. An example of an application is the earthing of high-voltage cables in HVDC systems or the bridging of parts of the high-voltage arresters used there.

Such so-called quick earth electrodes are usually provided in the prior art by gas-insulated switchgear (GIS). In many applications, for example in the DC voltage range of HVDC systems, the closing time of conventional quick-release devices is too long, which is why a further higher technical effort has to be made to ensure the protection of systems.

The object of the invention is to significantly shorten the closing time of make contact systems, in particular quick earth in the high voltage range compared to the prior art.

The solution to the problem consists in a make contact system for high-voltage applications with the features of patent claim 1.

The closing contact system according to the invention for high-voltage applications is characterized in that a vacuum interrupter with two switching contacts, which are designed in the form of plate contacts, is provided. At least one of the plate contacts is designed as a so-called moving contact which is driven by a drive. is coupled. Furthermore, the make contact system is characterized in that at least one of the plate contacts is rotationally symmetrically surrounded by a shield element, the shield element having an electrical conductivity that is less than 40 × 10 ⁶ S / m.

In the described invention, several measures that build on one another work together to solve the problem described. The first measure is to use a vacuum interrupter in contrast to the gas-insulated circuit used in the prior art. The vacuum interrupter comprises plate contacts, which can be designed to be relatively simple in terms of their geometry and which, due to the high electrical insulation property provided by the vacuum prevailing in the vacuum interrupter, require a very small contact distance. This in turn means that a shorter switching path has to be covered anyway, which significantly shortens the closing time. A further measure consists in that a shield element is arranged around at least one of the plate contacts, this shield element already preventing a rollover and thus allowing the plate contacts to come closer in the operating state, the shield element having a relatively low electrical conductivity in a further step, which has been found to be expedient according to the invention in order to further reduce the distance between the two plate contacts.

The sum of these measures leads to the fact that the present closing contact system for high-voltage applications has a significantly reduced closing time compared to the prior art, which means increased protection of the endangered components. The term plate contacts is basically understood to mean plate-shaped contacts that are has no magnetic field-controlling geometries, but these are also not harmful. Plate contacts are preferred to simple contact systems described in the

Closing contact system could be used because these contacts only have to close and do not have to interrupt any current flow.

It has been found that in particular a distance of 10 mm / 100 kV nominal voltage of the vacuum interrupter is a distance which is suitable for enabling very short closing times compared to the prior art. In this case, it is expedient if an average closing speed of the or of the contact which is moved during a closing process, that is to say the moving contact, is between 2 m / s and 8 m / s. The like closing speeds can be achieved by known drive systems.

Another feature that contributes to shortening the closing times between the plate contacts is the ratio between the distance from the contact surfaces of the plate contacts to their diameter. This is preferably between X and Y, particularly preferably between V and W.

It has proven to be expedient if the at least one screen element surrounds the moving contact. However, it may also be expedient to also provide a shield element for both the moving contact and for the second contact, which is generally designed as a fixed contact. It may also be expedient for the shield element to move at least part of the movement of the movement con along a switching axis, which leads to better shielding during the switching process. The shielding element preferably has an electrical conductivity of 40 x IO ^-6 S / m. The screen particularly preferably has element has a lower conductivity of 20 x 10 ⁶ S / m, which is ensured in particular when using iron or an iron alloy, in particular stainless steel.

In a further embodiment of the invention, the closing contact system is characterized in that the drive has a coupling member that serves for pretensioning a cable rotation pendulum kinematics, with this kinematics a rotary movement of a rotating body using winding cables into a translational movement of a winding body is converted. The winding body serves to drive the moving contact, the cable rotation kinematics is suitable to provide very high switching speeds, with additional bouncing of the contacts being prevented during the closing process.

Further embodiments of the invention and further features are explained in more detail with reference to the following figures. Since it is purely exemplary Ausgestaltungsfor men, which are shown very schematically to better identify the features and thus do not represent a restriction of the scope.

Show:

Figure 1 shows a make contact system comprising a vacuum

switching tube and a drive to achieve short closing times, when open,

FIG. 2 shows a make contact system according to FIG. 1 in the closed state of the contacts, FIG. 3 shows a make contact system according to FIG. 2 with a shielding element displaced along the switching axis,

FIG. 4 shows a make contact system according to FIG. 3 with a further change in the position of the screen element,

Figure 5 - 7, a coupling member as part of the drive of the

Closing contact system in different positions.

FIG. 1 shows a make contact system 1 which comprises a vacuum interrupter 28 and a drive 5. The vacuum interrupter 28 in turn comprises a housing 50, which on the one hand has a plurality of insulator elements 48 and a metallic interrupter chamber 49, a contact system 3 being arranged in the housing 50 of the vacuum interrupter 28. The contact system 3 comprises two switching contacts, which are designed in the form of plate contacts 4 and 6. In the present FIG. 1, the first plate contact 4 is designed in the form of a loading contact 30. The plate contacts 4, 6 are contacts which have essentially circular contact surfaces 34, which are characterized by a diameter 38. The contact surfaces 34 in turn are at a distance 36 from one another in an open position. The moving contact 30 is provided with a contact pin 44 which is isolated by a bellows 46 from the housing 50 of the vacuum interrupter 28, the contact bolt 44 shown here only schematically with a drive 5 is mechanically coupled. A possible configuration of the drive 5 is discussed in detail in FIGS. 5 to 7. When closing the vacuum interrupter 28, particularly in the high-voltage range, but also in medium-voltage applications, there are a few millimeters before touching the Plattenkon contacts 4, 6 to ignite an arc, not shown here, and to a high current flow. Depending on the amount of current flow and its duration until the final Kontaktbe contact, the arc begins to melt or melt the contact surfaces 34. Subsequently, the melted on contact surfaces 34 collide and weld if necessary. The melting is increased when the contacts bounce. This bouncing occurs especially at high closing speeds in conventional Federan drives.

When the contacts are subsequently opened, these sweat spots, which can also be configured very locally, are torn apart and there are sharp edges and tips on the contact surfaces 34. These sharp edges and tips, which are more in the microscopic range, cause canting of the electric field, which is equivalent to a reduction in the insulation capacity when the plate contacts 4, 6 are open. The insulation capacity can be reduced to such an extent by the tips that a flashover nevertheless takes place in vacuum tubes according to the prior art with a calculated rollover-free distance between the plate contacts 4, 6. This means that in the construction of the contact system 3, a corresponding safety distance must also be introduced, which, however, must also be bridged during the closing operation in the case of the application in question, and thereby lengthens the closing time.

In order to avoid excessive fields caused by sharp edges and peaks as the cause of the welding, a shield element 32, which also acts as a potential ring, is used at least one, preferably around both contacts 4, 6 is introduced. Preferably, the screen element 32 is installed around the moving contact 4, 30 in an open end position. This is the representation according to FIG. 1. Further arrangement possibilities of the screen element 32 are discussed in FIGS. 2 to 4.

The shielding element 32 thus prevents at least substantially the ignition of an arc in the open state, despite the welding mentioned and the resulting edges or tips, which means that the plate contacts 4, 6 can be positioned at a smaller distance 36 than this is the case according to the prior art. The reduced distance 36 contributes to a shorter one

Switching time at. A further contribution to shortening the switching time with existing drive 5 is the use of plate contacts 4, 6, which are particularly light in comparison to other contact versions, for example tulip / pin contacts in gas-insulated switchgear and, due to the lower mass with the same drive concept, a higher re Achieve closing speed, which in turn results in a shorter closing time. The closing speed is preferably between 2 m / s and 8 m / s. The plate contact 4, in particular the moving contact 30, can be further reduced with regard to its mass by various measures. For example, the contact pin 44 can be tubular, which leads to a reduced mass. A tubular design of the contact pin instead of a solid contact pin is possible in the present application as a make contact system, in particular a quick earth electrode, since a current does not have to be conducted over a long period of time. This contact pin 44 can also be made from a lighter material, for example from graphite or a non-metal. The application of graphite also as a coating of the contact bolt 44 can contribute to improving the vacuum. The features that lead to the reduction of the mass of the moving contact 30 or the contact bolt 44 also cause less bouncing of the contacts on one another during the closing process, which in turn results in less formation of welds or formation of tips and edges.

A further measure for avoiding mergers is the use of a high-melting or high-temperature-resistant material which is arranged at least in the area of the contact surfaces 34 of the contacts 4, 6. The addition of bismuth, tungsten, titanium and / or zirconium is an example of an alloying element of the contact material. This measure also reduces the melting of the contact surface 34 when the contacts 4, 6 approach.

It has proven to be expedient that the distance of the plate contacts 4, 6 in an open state is not more than 10 mm / 100 kV nominal voltage of the vacuum interrupter 28. With such a small distance 36, the described advantageous effects of the make contact system can be achieved. In particular, the distance 36 should not be less than 8 mm / 100 kV nominal voltage. It is expedient to provide a drive speed which is between 2 m / s and 8 m / s, which is made possible by a drive 5 according to FIGS. 5 to 7.

It has also been found that the ratio between the distance 36 of the contact surface 34 of the plate contacts 2, 4 to their diameter 38 is between X and Y, preferably between V and W. This ratio between distance and diameter is also suitable for the formation of a Suppress arc and thus also prevent welding and the formation of points and edges.

It has also been found to be expedient for the shield element to have an electrical conductivity which is lower than that of the copper. In particular, an electrical conductivity of the material of the screen element of less than

40 x IO ^-6 S / m means that on the one hand there is sufficient conductivity of the shield element 32, and on the other hand the formation of an arc is suppressed in a sustainable manner. A conductivity of the material of the shielding element 32, 33 is particularly advantageous, which is less than 20 x IO ^-6 S / m, in particular an iron-based alloy or stainless steel is expedient as the material of the shielding element 32, 33.

In the description of the representation according to Figures 2, 3 and 4, the arrangement of the screen element 32 will now be discussed. In Figure 1, two shield elements 32 are shown, which are fixedly positioned with respect to the switching axis and which are also arranged in the housing 50 of the vacuum interrupter 28 rotationally symmetrically around the plate contacts 4, 6. In an open state of the contacts 4, 6, the moving contact 4, 30 is withdrawn to such an extent that it closes with respect to a perpendicular to a switching axis 40 with an outer edge of the element 32, thereby achieving particularly good shielding. When the moving contact 4, 30 is closed, the shield element 32 described in FIG. 1 remains stationary, as shown in FIG.

An alternative is to move the screen element 32, which is designed as a movable screen element 33 in FIG. 3, at least partially during the closing process of the contact pair 3. Figure 3 shows a closed state of the contact pair 3, the shielding elements 32 and 33 with the contacts 4, 6 being moved towards one another and lying almost against one another.

Depending on the calculated and existing shielding effect and electrical fields, as shown in FIG. 4, the moving shielding element 33 can only be moved along a partial path along the switching axis 40 during the closing process, so that the shielding elements 32, 33 are somewhat spaced apart when the contact system 3 is closed from each other.

The following is an example of a possible drive 5 which is suitable for generating very high translatory speeds of the plate contacts, which are in the range of 2 m / s and 8 m / s. The centerpiece of the drive is a coupling element 2, described in more detail below, for pretensioning a rope-rotary pendulum kinematics, in which a rotary movement of a rotating body (10) is converted into a translatory movement of a winding body 8 with the aid of winding ropes 16.

Figures 1 to 3 show a schematic embodiment of a coupling member 2. With the coupling member 2, the contact system 3, consisting of the plate contacts in the form of plate contacts 4 and 6, is actuated, for this purpose the plate contact 4 is moved relative to the plate contact 6. The contact pair 3, which comprises the plate contacts 4, 6, are those which have already been explained schematically in FIGS. 1 to 4. When contacting the two plate contacts 4 and 6, a circuit is closed and a current flow is effected via the electrically conductive rod-shaped winding body 8 explained below and the contact system of the plate contacts 4 and 6. This current flow can by opening the contact system by moving the two plate contacts 4 and 6 apart again who the.

The plate contact 4, which is designed in the form of the moving contact 30, is mechanically coupled to a lower end of the winding body 8, which is also referred to below as the winding bar. In Figures 5 to 7, the Plattenkon tact 4 is directly at the lower end of the bobbin 8 Darge, which is a simplified representation that serves to illustrate the direct impact of the kinematics on the movement of the contact 4, 30. In principle, other components, such as the contact bolt 44, can be interposed between the winding body 8 and the plate contact 4, 30 in the coupling mentioned. However, it is also possible for portions of the winding body 8 to serve as contact bolts 44. The winding body 3 is linear, that is to say translationally displaceable, whereby it is guided along its longitudinal axis 14, since it cannot be rotated at. The longitudinal axis 14 preferably but not necessarily coincides with the switching axis 40.

On the winding body 8, a rotary body 10 is rotatably supported, i.e. the rotating body can rotate on the winding body. For this purpose, the rotating body 8 has a bore through which the rod-shaped winding body 8 projects. Between the winding body 8 and the rotating body 10, a bearing 13 is provided so that the rotation of the rotating body 10 is as frictionless and low-loss as possible.

The rotary body 8 in this example comprises two spaced disks or sides 11 and 12. Between these two sides 11 and 12 of the rotary body in this embodiment schematically represents the bearing 13, which is intended to illustrate that the rotary body 10 is rotatably mounted on the winding body 8.

In Figure 1, a position of the coupling member 2 is shown, the contacts 4 and 6 are opened in their greatest possible distance from each other. This distance is designated by the end position E with respect to the position of the contact 4, 30. FIG. 2 shows a middle position between the end position E and the end position E ′ shown in FIG. 3, in which the contacts 4, 30 and 6 are closed and current can flow through the contacts.

Starting with the position of the end position E in Figure 1, the closing process of the coupling member 2 will now be described. It must also be stated that the rotating body 10 is coupled to — in this example — two springs 18. The springs 18 are designed for tensile loading and are attached at one end to the rotating body 10 and fixed at another end to a fixed point 24 outside the coupling member 2.

In the end position E, in which a spring 18 has a greater preload than the spring 18 ', a lock 20 is seen before, which in turn is connected to an actuator 22. In this example, the locking device 20 is represented very schematically by a rod, the locking device 20 can be configured, for example, in the form of two intermeshing toothed rings, which is not explicitly shown here for the sake of clarity.

Furthermore, the coupling member comprises winding ropes 16 or 16 ', which are fastened between the rotating body 10 and the winding body 8, preferably provided with a certain pretension. The ropes 16 are each placed on the winding body 8 and as far as possible with a second attachment point attached to the outside of the disks 11 and 12 or to the upper and lower sides 11 and 12 of the rotary body 10. Under ropes, flexible structures such as tendons, wire ropes or aramid fibers are understood, which have a high modulus of elasticity on the one hand, in order to achieve the strongest possible prestress between the body 8 and the rotary body 10.

In the example according to FIG. 1, the ropes 16 'are wound in the lower region between the side 12 of the rotating body 10 and the plate contact 4 around the winding body by several turns. In the upper region of the coupling member 2, ie above the side 11 of the rotating body 10, the ropes 16 are not rotated in the position of the end position E according to FIG. If the locking device 20 is opened, for example caused by a signal which is forwarded to the actuator 22, the biasing of the springs 18 and 18 ', which are designed overall so that a resonator results, produces a rotary movement of the rotating body , through which the cables 16 'roll in the lower region of the winding body 8 and in turn the cables 16 in the upper region, above the rotating body 10, turn on the winding body 8. This position is shown in Figure 2. In the position according to FIG. 2, the springs 18 and 18 'are also essentially in an equilibrium position, with the springs 18 and 18' also being preloaded here. This equilibrium position according to Figure 2 is overcome due to the action of the two springs as a resonator and is set according to Figure 3, the position of the end position E ', in which the two plates contacts 4, 30 and 6 are closed.

The system is designed with regard to the preloads of the individual springs 18 and 18 'in such a way that not only is contact made between contacts 4 and 6, but also an offset force, that is to say an additional pressing force, acts on the plate contact 6 through the winding body 8 and the plate contact 4, 30. When the end position E 'is reached, the locking device 20, in turn triggered by the actuator 22, engages in the rotating body 10 so that the position of the rotating body 10 is held.

In the course of movement, which is shown between Figures 1 and 3, it is shown how the rotation of the rotary body 10 converts a rotational movement by winding the ropes 16 into a translational movement of the winding body 8 and thus also of the switching contact 4. The translatory or linear movement of the winding body 8 can take place in both directions. The closing process described here can be reversibly described starting from FIG. 3 via the position of FIG. 2 and returning to FIG. 1, with a translatory movement of the winding body 8 along its longitudinal axis 14 in the direction of the end position E being fully drawn.

Since the pair of springs 18 and 18 'acts as a resonator, this movement can very often take place without great friction losses. The friction losses are very low because the friction that is transmitted via the ropes 16 and 16 'is also low and the best possible storage of the ro tationskörper with respect to the winding body 8 takes place. As Fe, 18, 18 'are shown here purely schematically helical spring, there can be various types of springs, such as spiral springs or gas pressure springs, which can also be constructed in a rotary manner and can be integrated into the winding body, to be used.

The rotary movement of the rotating body 10 is designed in such a way that the rotating body 10 and a closing process makes a rotation of about 90 ° in each direction. The switching time, that is the time that the coupling member needs to get from the end position E 'to the end position E and vice versa, by the stiffness of the springs 18 used and by the inertia, i.e. the mass of the rotating body 10, which also acts as a flywheel, depending. The angular velocity Q of the Rotati onskörpers 10 is directly proportional to the root of the ratio of spring stiffness, that is, the spring constant K and the mass m of the rotating body 10, exemplarily expressed by the equation

Q ~ (K / m) ° _' ⁵ .

The energy of the rotary body is set so that the desired Q, that is, the desired Winkelge speed and the desired switching time for the respective switching operation results, with about 95% of the total energy of the system being incorporated into the switching operation. Due to the very low-loss described switching system or coupling element, approximately 1.5 J of energy is lost in the system in an exemplary switching operation. In a conventional switching operation with a conventional drive, 20 to 30 times the energy per switching operation is lost with the same power and with a comparable size of the coupling member. This means that this energy is lost when the two plate contacts 4 and 6 strike, which means that this energy separates the plate contacts several times in a so-called bouncing process and brings them together again, similar to what a hammer does is hit on the boss. This bouncing process is extremely undesirable when switching the high-voltage system, since it does not allow uniform and quick contact establishment. Due to the low-loss coupling ment member according to Figures 1 to 3, this bouncing process is reduced to a minimum.

LIST OF REFERENCE NUMBERS

1 make contact system

2 coupling link

3 pairs of contacts

4 first switching contact

5 drive

6 second switching contact

8 rod-shaped winding body

10 rotating bodies

11 one side R body

12 second side R-body

13 bearings

14 longitudinal axis

16 page

18 feathers

20 locking

22 actuator

24 Spring attachment point

28 vacuum interrupter

30 moving contact

32 screen element

33 movably mounted umbrella

34 contact surfaces

36 Distance contact surface

38 diameter contact surfaces

40 switching axis

42 Rope rotation pendulum kinematics

44 contact bolts

46 bellows

48 isolator

49 metallic interrupter

50 housing

Claims

claims

1. Closing contact system for high-voltage applications, characterized in that a vacuum interrupter (28) with two switching contacts in the form of plate contacts (2, 4) is provided, of which at least one, one with a drive

(5) is a coupled moving contact (30) and at least one plate contact (2, 4) is rotationally symmetrically surrounded by a shield element (32) and the shield element (32) has an electrical conductivity that is less than 40 10 ⁶ S / m ,

2. Closing contact system according to claim 1, characterized in that the distance between the plate contacts (2, 4) in the opened state is less than 10 mm per 100 kV nominal voltage.

3. Closing contact system according to claim 1 or 2, characterized in that an average closing speed which occurs during the movement of the at least one moving plate contact (30) is between 2 m / s and 8 m / s.

4. Closing contact system according to one of claims 1 to 3, characterized in that the ratio between the stand (36) of contact surfaces (34) of the plate contacts (2, 4) to their diameter (38) is between X and Y.

5. Closing contact system according to claim 4, characterized in that the ratio between the distance (36) from Kon contact surfaces (34) of the plate contacts (2, 4) to their diameter (38) is between V and W.

6. Closing contact system according to one of the preceding claims, characterized in that the at least one shield element (32) surrounds the moving contact (30).

7. Closing contact system according to claim 6, characterized in that the shield element (32) is movably mounted along a switching axis (40).

8. Closing contact system according to one of the preceding claims, characterized in that the electrical conductivity of the shielding element (32, 33) has less than 20 IO ^-6 S / m.

9. Closing contact system according to one of claims 2 to 8, characterized in that the distance (36) of the contact surfaces (34) of the plate contact (2, 4) in the open state is less than 8 mm per 100 kV nominal voltage.

10. Closing contact system according to one of the preceding claims, characterized in that the shield element (32, 33) is formed on the basis of iron or an iron alloy.

11. Closing contact system according to one of the preceding claims, characterized in that the drive (5) comprises a coupling member (2) for pretensioning a rope rotation pendulum kinematics, in which a rotational movement of a rotating body (10) with the aid of winding ropes (16 ) is converted into a translational movement of a winding body (8).